Implement a more comprehensive way to get connection information

lib/plug/adapters/test/conn.ex

@@ -33,7 +33,13 @@ defmodule Plug.Adapters.Test.Conn do
           address: {127, 0, 0, 1},
           port: 111_317,
           ssl_cert: nil
-        })
+        }),
+      sock_data:
+        get_from_adapter(conn, :get_sock_data, %{
+          address: {127, 0, 0, 1},
+          port: 111_318
+        }),
+      ssl_data: get_from_adapter(conn, :get_ssl_data, nil)
     }
 
     conn_port = if conn.port != 0, do: conn.port, else: 80
@@ -140,6 +146,14 @@ defmodule Plug.Adapters.Test.Conn do
     Map.fetch!(payload, :peer_data)
   end
 
+  def get_sock_data(payload) do
+    Map.fetch!(payload, :sock_data)
+  end
+
+  def get_ssl_data(payload) do
+    Map.fetch!(payload, :ssl_data)
+  end
+
   def get_http_protocol(payload) do
     Map.fetch!(payload, :http_protocol)
   end

lib/plug/conn.ex

@@ -638,6 +638,36 @@ defmodule Plug.Conn do
     adapter.get_peer_data(payload)
   end
 
+  @doc """
+  Returns the request sock (local) data.
+
+  It raises if the adapter does not provide this metadata.
+  """
+  @spec get_sock_data(t) :: Plug.Conn.Adapter.sock_data()
+  def get_sock_data(%Conn{adapter: {adapter, payload}}) do
+    if function_exported?(adapter, :get_sock_data, 1) do
+      adapter.get_sock_data(payload)
+    else
+      raise "get_sock_data not supported by #{inspect(adapter)}"
+    end
+  end
+
+  @doc """
+  Returns SSL data for the connection.
+
+  If the connection is not SSL, returns nil.
+
+  It raises if the adapter does not provide this metadata.
+  """
+  @spec get_ssl_data(t) :: Plug.Conn.Adapter.ssl_data()
+  def get_ssl_data(%Conn{adapter: {adapter, payload}}) do
+    if function_exported?(adapter, :get_ssl_data, 1) do
+      adapter.get_ssl_data(payload)
+    else
+      raise "get_ssl_data not supported by #{inspect(adapter)}"
+    end
+  end
+
   @doc """
   Returns the HTTP protocol and version.
 

lib/plug/conn/adapter.ex

@@ -11,6 +11,11 @@ defmodule Plug.Conn.Adapter do
           port: :inet.port_number(),
           ssl_cert: binary | nil
         }
+  @type sock_data :: %{
+          address: :inet.ip_address(),
+          port: :inet.port_number()
+        }
+  @type ssl_data :: :ssl.connection_info() | nil
 
   @doc """
   Function used by adapters to create a new connection.
@@ -166,10 +171,21 @@ defmodule Plug.Conn.Adapter do
   """
   @callback get_peer_data(payload) :: peer_data()
 
+  @doc """
+  Returns sock (local-side) information such as the address and port.
+  """
+  @callback get_sock_data(payload) :: sock_data()
+
+  @doc """
+  Returns details of the negotiated SSL connection, if present. If the connection is not SSL,
+  returns nil
+  """
+  @callback get_ssl_data(payload) :: ssl_data()
+
   @doc """
   Returns the HTTP protocol and its version.
   """
   @callback get_http_protocol(payload) :: http_protocol
 
-  @optional_callbacks push: 3
+  @optional_callbacks push: 3, get_sock_data: 1, get_ssl_data: 1
 end

lib/plug/test.ex

@@ -208,6 +208,24 @@ defmodule Plug.Test do
     end)
   end
 
+  @doc """
+  Puts the sock data.
+  """
+  def put_sock_data(conn, sock_data) do
+    update_in(conn.adapter, fn {adapter, payload} ->
+      {adapter, Map.put(payload, :sock_data, sock_data)}
+    end)
+  end
+
+  @doc """
+  Puts the ssl data.
+  """
+  def put_ssl_data(conn, ssl_data) do
+    update_in(conn.adapter, fn {adapter, payload} ->
+      {adapter, Map.put(payload, :ssl_data, ssl_data)}
+    end)
+  end
+
   @doc """
   Puts a request cookie.
   """

test/plug/adapters/test/conn_test.exs

@@ -185,6 +185,18 @@ defmodule Plug.Adapters.Test.ConnTest do
     assert peer_data == Plug.Conn.get_peer_data(conn)
   end
 
+  test "use custom sock data" do
+    sock_data = %{address: {127, 0, 0, 1}, port: 111_318}
+    conn = conn(:get, "/") |> put_sock_data(sock_data)
+    assert sock_data == Plug.Conn.get_sock_data(conn)
+  end
+
+  test "use custom ssl data" do
+    ssl_data = %{address: {127, 0, 0, 1}, port: 111_317}
+    conn = conn(:get, "/") |> put_ssl_data(ssl_data)
+    assert ssl_data == Plug.Conn.get_ssl_data(conn)
+  end
+
   test "push/3 sends message including path and headers" do
     ref = make_ref()
 

test/plug/conn_test.exs

@@ -126,6 +126,13 @@ defmodule Plug.ConnTest do
              port: 111_317,
              ssl_cert: nil
            }
+
+    assert get_sock_data(conn) == %{
+             address: {127, 0, 0, 1},
+             port: 111_318
+           }
+
+    assert is_nil(get_ssl_data(conn))
   end
 
   test "path_info" do